Light-emitting devices

ABSTRACT

A light-emitting device comprises a semiconductor layer sequence comprising a first semiconductor layer having a first electrical conductivity, a second semiconductor layer having a second electrical conductivity, and an active layer interposed between the first semiconductor layer and the second semiconductor layer; a plurality of beveled trenches formed in the semiconductor layer sequence; a plurality of protruding structures respectively formed in the plurality of beveled trenches; a dielectric layer formed on the second semiconductor layer and an inner sidewall of the plurality of beveled trenches; a reflecting layer interposed between the semiconductor layer sequence and the dielectric layer; and a metal layer formed along the inner sidewall of the plurality of beveled trenches, wherein the dielectric layer, the reflecting layer and the metal layer are overlapping, the plurality of protruding structures and the reflecting layer are not overlapping.

REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 15/273,439, filed on Sep. 22, 2016, which is acontinuation application of U.S. patent application Ser. No. 14/705,453,filed on May 6, 2015, which is a continuation application of U.S. patentapplication Ser. No. 14/093,924, filed on Dec. 2, 2013, now issued,which claims the right of priority based on U.S. application Ser. No.13/221,369, filed on Aug. 30, 2011, and U.S. provisional applicationSer. No. 61/378,197, filed on Aug. 30, 2010, and the contents of whichare hereby incorporated by references in their entireties.

TECHNICAL FIELD

The application relates to a light-emitting device, and moreparticularly, to a light-emitting device with a connection structure.

DESCRIPTION OF BACKGROUND ART

The light-emitting diode (LED) is a solid state semiconductor device,which has been broadly used as a light-emitting device. Thelight-emitting device structure at least comprises a p-typesemiconductor layer, an n-type semiconductor layer, and an active layer.The active layer is formed between the p-type semiconductor layer andthe n-type semiconductor layer. The structure of the light-emittingdevice generally comprises III-V group compound semiconductor such asgallium phosphide, gallium arsenide, or gallium nitride. Thelight-emitting principle of the LED is the transformation of electricalenergy to optical energy by applying electrical current to the p-njunction to generate electrons and holes. Then, the LED emits light whenthe electrons and the holes combine.

FIG. 1 illustrates a cross-sectional diagram of a conventionallight-emitting device before bonding process. The light-emitting devicecomprises a semiconductor layer sequence 10 a provided with a first mainside 18 and a second main side 181, comprising a first semiconductorlayer 11, a second semiconductor layer 13, and an active layer 12 formedbetween the first semiconductor layer 11 and the second semiconductorlayer 13, which can produce electromagnetic radiation. A trench isformed in the semiconductor layer sequence 10 a by wet etch or dry etch.A dielectric layer 14 is formed on the inner sidewall of the trench toelectrically insulate the second semiconductor layer 13 and the activelayer 12. Then, an electrically conductive material is filled into theinsulated trench, so a first metal layer 15 is formed. A reflectinglayer 16 is formed between the semiconductor layer sequence 10 a and thedielectric layer 14. A void 17 is an area not occupied by the firstmetal layer 15. A first connection layer 101 formed on a carriersubstrate 102 is used to connect the first metal layer 15. The firstconnection layer 101 and the first metal layer 15 are connected togetherin an electrically conductive manner. As shown in FIG. 1, after formingthe first connection layer 101 and the first metal layer 15, thesemiconductor layer sequence 10 a is connected to the carrier substrate102 by metal bonding or glue bonding.

FIG. 2A illustrates a cross-sectional diagram of a conventionallight-emitting device 20. As shown in FIG. 2A, connecting failureproblem arises in the bonding process. FIG. 2A shows the result of thebonding process after a first metal layer 25 is connected to a firstconnection layer 201. However, because the trench is deep, it is noteasy to fill the trench with electrically conductive material, and theprofile of the trench is concave after the filling process. While thefirst metal layer 25 is connected to the first connection layer 201 of acarrier substrate 202, a void 204 is formed between the first metallayer 25 and the first connection layer 201. Thus, the connection areabetween the first metal layer 25 and the first connection layer 201 issmall and the resistance of the light-emitting device 20 is thereforeraised. As shown in FIG. 2B, the peripheral area of the trench 200 isoccupied by the first metal layer 25, and the internal area not occupiedby the first metal layer 25 forms the void 204.

SUMMARY OF THE APPLICATION

An object of the present application is to reduce the size of the voidformed in the filling process of the trench and increase the connectionarea between the first metal layer and the first connection layer of thecarrier substrate for electrical characteristics and light emissionefficiency improvement.

A light-emitting device of an embodiment of the present applicationcomprises a semiconductor layer sequence provided with a first mainside, a second main side, and an active layer; a beveled trench formedin the semiconductor layer sequence, having a top end close to thesecond main side, a bottom end, and an inner sidewall connecting the topend and the bottom end. In the embodiment, the inner sidewall is aninclined surface. The light-emitting device further comprises adielectric layer disposed on the inner sidewall of the beveled trenchand the second main side; a first metal layer formed on the dielectriclayer; a carrier substrate; and a first connection layer connecting thecarrier substrate and the semiconductor layer sequence.

A light-emitting device comprises a semiconductor layer sequencecomprising a first semiconductor layer having a first electricalconductivity, a second semiconductor layer having a second electricalconductivity, and an active layer interposed between the firstsemiconductor layer and the second semiconductor layer; a plurality ofprotruding structures; a plurality of beveled trenches in thesemiconductor layer sequence and respectively accommodating theplurality of protruding structures; a dielectric layer on the secondsemiconductor layer and an inner sidewall of the plurality of beveledtrenches, wherein the dielectric layer comprises a surface perpendicularto a thickness direction of the semiconductor layer sequence; a metallayer formed along the inner sidewall of the plurality of beveledtrenches and extending to the surface of the dielectric layer, whereinthe metal layer is insulated from the second semiconductor layer by thedielectric layer; and a first electrode formed on the plurality ofprotruding structures.

A light-emitting device comprises a semiconductor layer sequencecomprising a first semiconductor layer having a first electricalconductivity, a second semiconductor layer having a second electricalconductivity, and an active layer interposed between the firstsemiconductor layer and the second semiconductor layer; a plurality ofbeveled trenches formed in the semiconductor layer sequence; a pluralityof protruding structures respectively formed in the plurality of beveledtrenches; a dielectric layer formed on the second semiconductor layerand an inner sidewall of the plurality of beveled trenches; a reflectinglayer interposed between the semiconductor layer sequence and thedielectric layer; and a metal layer formed along the inner sidewall ofthe plurality of beveled trenches, wherein the dielectric layer, thereflecting layer and the metal layer are overlapping, the plurality ofprotruding structures and the reflecting layer are not overlapping.

A light-emitting device comprises a semiconductor layer sequencecomprising a first semiconductor layer having a first electricalconductivity, a second semiconductor layer having a second electricalconductivity, and an active layer interposed between the firstsemiconductor layer and the second semiconductor layer; a beveled trenchformed in the semiconductor layer sequence; a protruding structureformed in the beveled trench; a dielectric layer formed on the secondsemiconductor layer and an inner sidewall of the beveled trench; areflecting layer interposed between the semiconductor layer sequence andthe dielectric layer; a metal layer formed along the inner sidewall ofthe beveled trench; a carrier substrate; and a void between the metallayer and the carrier substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional diagram of a conventionallight-emitting device before bonding process;

FIG. 2A illustrates a cross-sectional diagram of a conventionallight-emitting device;

FIG. 2B illustrates a top-view diagram of a trench shown in FIG. 2A;

FIG. 3A illustrates a cross-sectional diagram according to the firstembodiment of the present application;

FIG. 3B illustrates a top-view diagram of a beveled trench shown in FIG.3A;

FIG. 4A illustrates a cross-sectional diagram according to the secondembodiment of the present application;

FIG. 4B illustrates a top-view diagram of a beveled trench shown in FIG.4A;

FIG. 5A illustrates a cross-sectional diagram according to the thirdembodiment of the present application; and

FIG. 5B illustrates a top-view diagram of a beveled trench shown in FIG.5A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiment of the application is illustrated in detail, and isplotted in the drawings. The same or the similar part is illustrated inthe drawings and the specification with the same number.

FIG. 3A illustrates a cross-sectional diagram of a light-emitting device30 according to the first embodiment of the present application. In theembodiment, the light-emitting device 30 comprises a semiconductor layersequence 30 a provided with a first main side 39, a second main side391, and an active layer 32; a beveled trench formed in thesemiconductor layer sequence 30 a, having a top end 306 close to thesecond main side 391, a bottom end 305, and an inner sidewall 307connecting the top end 306 and the bottom end 305. In the embodiment,the inner sidewall 307 is an inclined surface. The light-emitting device30 further comprises a dielectric layer 34 disposed on the innersidewall 307 of the beveled trench and the second main side 391; a firstmetal layer 35 formed on the dielectric layer 34; a carrier substrate302; and a first connection layer 301 connecting the carrier substrate302 and the semiconductor layer sequence 30 a. The semiconductor layersequence 30 a further comprises a first semiconductor layer 31 having afirst electrical conductivity formed near the first main side 39, and asecond semiconductor layer 33 having a second electrical conductivityformed near the second main side 391, wherein the active layer 32 isinterposed between the first semiconductor layer 31 and the secondsemiconductor layer 33. The material of the active layer 32 can compriseInGaN-based material, AlGaAs-based material, or AlInGaP-based material.

The beveled trench is formed in the semiconductor layer sequence 30 a bywet etch or dry etch. The bottom end 305 of the beveled trench is formedin the first semiconductor layer 31 of the semiconductor layer sequence30 a, and the top end 306 of the beveled trench is formed close to thesecond main side 391. The area near the top end 306 of the beveledtrench is larger than the area near the bottom end 305 of the beveledtrench. The dielectric layer 34 is formed on the inner sidewall 307 ofthe beveled trench to electrically insulate the second semiconductorlayer 33 and the active layer 32. The material of the dielectric layer34 comprises silicon oxide, silicon nitride, magnesium oxide, tantalumoxide, titanium oxide, or polymer. In addition, in order to increase theluminous efficiency, a reflecting layer 36 is interposed between thesemiconductor layer sequence 30 a and the dielectric layer 34. Thematerial of the reflecting layer 36 comprises metal or metal alloy.

Then, the beveled trench is filled by the first metal layer 35. Thematerial of the first metal layer 35 comprises metal like Ni, Au, Ti,Cr, Au, Zn, Al, Pt, or the combination thereof. During the fillingprocess of the first metal layer 35, a concave area is formed. Thus, asecond filling process of the beveled trench is performed via anadditional local electro-plating process, wherein the first metal layer35 functions as the seed layer, and a conductive protruding structure 38is formed selectively on the concave area of the beveled trench by theelectro-plating process. The material of the conductive protrudingstructure 38 comprises conductive metal like Ni, Au, Ti, Cr, Au, Zn, Al,Pt, or the combination thereof. Therefore, the total connecting areabetween the first metal layer 35 and the first connection layer 301 isenlarged as shown in FIG. 3B compared with FIG. 2B, and the connectionresistance can be reduced. As shown in FIG. 3B, the top view of thebeveled trench 300 is circular or elliptic, and the top view of theconductive protruding structure 38 is circular or elliptic. Thecircumference of the conductive protruding structure 38 is smaller thanthe circumference of the beveled trench. The conductive protrudingstructure 38 is accommodated in the beveled trench. A void 304 disposedbetween the first metal layer 35 and the conductive protruding structure38 is not filled by the first metal layer 35 or the material of theconductive protruding structure 38. As shown in FIG. 3B, the peripheralarea of the beveled trench 300 is occupied by the first metal layer 35,the internal area of the beveled trench 300 is occupied by theconductive protruding structure 38, and the void 304 is formed betweenthe first metal layer 35 and the conductive protruding structure 38.With the conductive protruding structure 38, the total connection areabetween the first metal layer 35 and the first connection layer 301 isenlarged as shown in FIG. 3B compared with FIG. 2B, and the connectionresistance is reduced.

After forming the first metal layer 35 and the conductive protrudingstructure 38, the semiconductor layer sequence 30 a is connected to thecarrier substrate 302 by the first connection layer 301. The material ofthe first connection layer 301 comprises metal like Au, Sn, Cr, Zn, Ni,Ti, Pt, or the combination thereof. The carrier substrate 302 is aconductive substrate comprising metal or metal alloy like Cu, Al, Sn,Zn, Cd, Ni, Co, W, Mo, or the combination thereof. The light-emittingdevice 30 according to the embodiment of the present application furthercomprises a first electrode 303 formed on the carrier substrate 302 andelectrically connected to the first semiconductor layer 31, and a secondelectrode 37 electrically connected to the second semiconductor layer33.

FIG. 4A illustrates a cross-sectional diagram of a light-emitting device40 according to the second embodiment of the present application. In theembodiment, the light-emitting device 40 comprises a semiconductor layersequence 40 a provided with a first main side 49, a second main side491, and an active layer 42; a beveled trench formed in thesemiconductor layer sequence 40 a having a top end 406 close to thesecond main side 491, a bottom end 405, and an inner sidewall 407connecting the top end 406 and the bottom end 405. In the embodiment,the inner sidewall 407 is an inclined surface. The light-emitting device40 further comprises a dielectric layer 44 disposed on the innersidewall 407 of the beveled trench and the second main side 491; a firstmetal layer 45 formed on the dielectric layer 44; a carrier substrate402; and a first connection layer 401 connecting the carrier substrate402 and the semiconductor layer sequence 40 a. The semiconductor layersequence 40 a further comprises a first semiconductor layer 41 having afirst electrical conductivity formed near the first main side 49, and asecond semiconductor layer 43 having a second electrical conductivityformed near the second main side 491, wherein the active layer 42 isinterposed between the first semiconductor layer 41 and the secondsemiconductor layer 43. The material of the active layer 42 can compriseInGaN-based material, AlGaAs-based material, or AlInGaP-based material.

The beveled trench is formed in the semiconductor layer sequence 40 a bywet etch or dry etch. The bottom end 405 of the beveled trench is formedin the first semiconductor layer 41 of the semiconductor layer sequence40 a, and the top end 406 of the beveled trench is formed close to thesecond main side 491. The area near the top end 406 of the beveledtrench is larger than the area near the bottom end 405 of the beveledtrench. Partial of the semiconductor layer sequence 40 a in the beveledtrench is remained by the conventional lithography and etch method, thatis, there is a conductive protruding structure 48 formed in the beveledtrench. The conductive protruding structure 48 comprises a layersequence substantially comprising the same material as the semiconductorlayer sequence 40 a. The material of the layer sequence of theconductive protruding structure 48 comprises one or more than oneelement selecting from a group consisting of gallium (Ga), aluminum(Al), indium (In), phosphor (P), nitrogen (N), zinc (Zn), cadmium (Cd),arsenide (As), silicon (Si), and selenium (Se). Because not all of thesemiconductor layers in the beveled trench are etched away, the spaceneeded to be filled is not deep as the structure shown in FIG. 2A, andit is easier for the first metal layer 45 to fill the space in thebeveled trench. The material of the first metal layer 45 comprises Ni,Au, Ti, Cr, Au, Zn, Al, Pt, or the combination thereof. Similarly, thetotal connecting area between the first metal layer 45 and the firstconnection layer 401 is enlarged as shown in FIG. 4B compared with FIG.2B and the connection resistance can be reduced. As shown in FIG. 4B,the top view of the beveled trench 400 is circular or elliptic, and thetop view of the conductive protruding structure 48 is circular orelliptic. The circumference of the conductive protruding structure 48 issmaller than the circumference of the beveled trench 400. A void 404disposed in the first metal layer 45 is not filled by the first metallayer 45 or the material of the conductive protruding structure 48. Asshown in FIG. 4B, the peripheral area of the beveled trench 400 isoccupied by the first metal layer 45, the internal area 45′ of thebeveled trench 400 is occupied by the same material of the first metallayer 45, and the void 404 is formed in the first metal layer 45. Withthe conductive protruding structure 48, the total connection areabetween the first metal layer 45 and the first connection layer 401 isenlarged as shown in FIG. 4B compared with FIG. 2B, and the connectionresistance is reduced.

The dielectric layer 44 is formed on the inner sidewall 407 of thebeveled trench and the surface of the conductive protruding structure 48to electrically insulate the second semiconductor layer 43 and theactive layer 42. The material of the dielectric layer 44 comprisessilicon oxide, silicon nitride, magnesium oxide, tantalum oxide,titanium oxide, or polymer. In addition, in order to increase theluminous efficiency, a reflecting layer 46 is interposed between thesemiconductor layer sequence 40 a and the dielectric layer 44. Thematerial of the reflecting layer 46 comprises metal or metal alloy.

After forming the first metal layer 45 and the conductive protrudingstructure 48, the semiconductor layer sequence 40 a is connected to thecarrier substrate 402 by the first connection layer 401. The material ofthe first connection layer 401 comprises metal like Au, Sn, Cr, Zn, Ni,Ti, Pt, or the combination thereof. The carrier substrate 402 is aconductive substrate comprising metal or metal alloy like Cu, Al, Sn,Zn, Cd, Ni, Co, W, Mo, or the combination thereof. The light-emittingdevice 40 according to the embodiment of the present application furthercomprises a first electrode 403 formed on the carrier substrate 402 andelectrically connected to the first semiconductor layer 41, and a secondelectrode 47 electrically connected to the second semiconductor layer43.

FIG. 5A illustrates a cross-sectional diagram of a light-emitting device50 according to the third embodiment of the present application. In theembodiment, the light-emitting device 50 comprises a semiconductor layersequence 50 a provided with a first main side 60, a second main side601, and an active layer 52; a beveled trench formed through thesemiconductor layer sequence 50 a, having a top end 506 close to thesecond main side 601, a bottom end 505, and an inner sidewall 507connecting the top end 506 and the bottom end 505. In the embodiment,the inner sidewall 507 is an inclined surface. The light-emitting device50 further comprises a dielectric layer 54 disposed on the innersidewall 507 of the beveled trench and the second main side 601; a firstmetal layer 55 formed on the dielectric layer 54; a carrier substrate502; and a first connection layer 501 connecting the carrier substrate502 and the semiconductor layer sequence 50 a. The semiconductor layersequence 50 a further comprises a first semiconductor layer 51 having afirst electrical conductivity formed near the first main side 60 of thesemiconductor layer sequence 50 a, and a second semiconductor layer 53having a second electrical conductivity formed near the second main side601 of the semiconductor layer sequence 50 a, wherein the active layer52 is interposed between the first semiconductor layer 51 and the secondsemiconductor layer 53. The material of the active layer 52 can compriseInGaN-based material, AlGaAs-based material, or AlInGaP-based material.

During the filling process of the beveled trench, the beveled trenchcannot be fully filled with the conductive material because there issome gas remained in the beveled trench. After the conductive materialis filled into the beveled trench, the conductive material is solidifiedby cooling. In the cooling process, the gas goes out and the concavearea forms. Therefore, in the embodiment of the present application, thebeveled trench is formed through the semiconductor layer sequence 50 aby wet etch or dry etch. The area near the top end 506 of the beveledtrench is larger than the area near the bottom end 505 of the beveledtrench. The bottom end 505 of the beveled trench is formed on the firstmain side 60, and the top end 506 of the beveled trench is formed nearthe second main side 601.

The dielectric layer 54 is formed on the inner sidewall 507 of thebeveled trench to electrically insulate the second semiconductor layer53 and the active layer 52. The material of the dielectric layer 54comprises silicon oxide, silicon nitride, magnesium oxide, tantalumoxide, titanium oxide, or polymer. In addition, in order to increase theluminous efficiency, a reflecting layer 56 is interposed between thesemiconductor layer sequence 50 a and the dielectric layer 54. Thematerial of the reflecting layer 56 comprises metal or metal alloy.

In the light-emitting device 50 of the present application, there is noremaining gas left in the beveled trench, and the first metal layer 55can overflow the whole beveled trench to make a back connection 59. Theback connection 59 comprising the same material as the first metal layer55 is formed on the first main side 60 and electrically connected to thefirst semiconductor layer 51. That is, the first semiconductor layer 51is electrically connected to the first connection layer 501 by the firstmetal layer 55 through the first main side 60 without any vacant spacethere between. Therefore, the total connecting area between the firstmetal layer 55 and the first connection layer 501 is enlarged as shownin FIG. 5B compared with FIG. 2B, and the connection resistance can bereduced. As shown in FIG. 5B, the top view of the beveled trench 500 iscircular or elliptic, and the beveled trench 500 is fully filled by thefirst metal layer 55 without any vacant space.

After forming the first metal layer 55 in the beveled trench, thesemiconductor layer sequence 50 a is connected to the carrier substrate502 by the first connection layer 501. The material of the firstconnection layer 501 comprises metal like Au, Sn, Cr, Zn, Ni, Ti, Pt, orthe combination thereof. The carrier substrate 502 is a conductivesubstrate comprising metal or metal alloy like Cu, Al, Sn, Zn, Cd, Ni,Co, W, Mo, or the combination thereof.

The light-emitting device 50 according to the embodiment of the presentapplication further comprises a first electrode 503 formed on thecarrier substrate 502 and electrically connected to the firstsemiconductor layer 51, and a second electrode 57 electrically connectedto the second semiconductor layer 53. The principle and the efficiencyof the present application illustrated by the embodiments above are notthe limitation of the application. Any person having ordinary skill inthe art can modify or change the aforementioned embodiments. Therefore,the protection range of the rights in the application will be listed asthe following claims.

What is claimed is:
 1. A light-emitting device, comprising: asemiconductor layer sequence comprising a first semiconductor layer, asecond semiconductor layer, and an active layer interposed between thefirst semiconductor layer and the second semiconductor layer; a beveledtrench formed in the semiconductor layer sequence, comprising a top end,a bottom end exposing the first semiconductor layer and an innersidewall connecting the top end and the bottom end; a protrudingstructure formed inside the beveled trench and protruding outside thetop end of the beveled trench in a thickness direction of thesemiconductor layer sequence; a dielectric layer formed on the secondsemiconductor layer and the inner sidewall of the beveled trench; areflecting layer interposed between the second semiconductor layer andthe dielectric layer; and a metal layer formed along the inner sidewallof the beveled trench to extend outside the beveled trench, wherein thedielectric layer, the reflecting layer and the metal layer areoverlapping.
 2. The light-emitting device according to claim 1, whereinthe plurality of protruding structures is surrounded by the reflectinglayer.
 3. The light-emitting device according to claim 1, wherein themetal layer and the protruding structure are overlapping.
 4. Thelight-emitting device according to claim 1, further comprising aplurality of beveled trenches and a plurality of protruding structuresrespectively formed in the plurality of beveled trenches, wherein theplurality of protruding structures are separated from each other in across-sectional view of the light-emitting device, and the metal layercomprises a circular shape in a top view of the light-emitting device.5. The light-emitting device according to claim 1, wherein thedielectric layer comprises a surface perpendicular to the thicknessdirection of the semiconductor layer sequence, and the metal layerextends onto the surface of the dielectric layer.
 6. The light-emittingdevice according to claim 1, wherein the protruding structure does notform on the second semiconductor layer.
 7. The light-emitting deviceaccording to claim 1, wherein the protruding structure and the beveledtrench comprise a similar shape from a top view of the light-emittingdevice.
 8. The light-emitting device according to claim 7, wherein acircumference of the protruding structure is smaller than acircumference of the beveled trench.
 9. The light-emitting deviceaccording to claim 1, wherein the material of the protruding structurecomprises metal.
 10. The light-emitting device according to claim 1,wherein the top end comprises an area larger than an area of the bottomend.
 11. The light-emitting device according to claim 1, wherein theactive layer comprises InGaN-based material, AlGaAs-based material, orAlInGaP-based material.
 12. The light-emitting device according toclaims 1, further comprising a carrier substrate and a connection layerformed between the carrier substrate and the semiconductor layersequence, wherein the material of the connection layer comprises metal.13. The light-emitting device according to claim 12, wherein the carriersubstrate is conductive.
 14. The light-emitting device according toclaim 12, wherein the connection layer is formed between the metal layerand the carrier substrate.
 15. The light-emitting device according toclaim 4, further comprising a first electrode formed on the plurality ofprotruding structures.
 16. The light-emitting device according to claim15, further comprising a second electrode electrically connected to thesecond semiconductor layer, wherein the reflecting layer comprises aportion beyond the semiconductor layer sequence and the second electrodeis on the portion of the reflecting layer.
 17. The light-emitting deviceaccording to claim 16, wherein the reflecting layer comprises metalmaterial.
 18. A light-emitting device, comprising: a semiconductor layersequence comprising a first semiconductor layer having a firstelectrical conductivity, a second semiconductor layer having a secondelectrical conductivity, and an active layer interposed between thefirst semiconductor layer and the second semiconductor layer; a beveledtrench formed in the semiconductor layer sequence; a protrudingstructure only formed at the beveled trench; a dielectric layer formedon the second semiconductor layer and an inner sidewall of the beveledtrench; a reflecting layer interposed between the semiconductor layersequence and the dielectric layer; a metal layer formed along the innersidewall of the beveled trench and extended outside the beveled trench;a carrier substrate; and a void formed at a position under andcorresponding to a position of the beveled trench.
 19. Thelight-emitting device according to claim 18, wherein the dielectriclayer, the reflecting layer and the metal layer are overlapping, and theprotruding structure and the reflecting layer are not overlapping. 20.The light-emitting device according to claim 18, further comprising afirst connection layer between the carrier substrate and the metallayer, wherein the void is between the metal layer and the firstconnection layer.